95Sierra2500

Check your fuel pressure. 9 times out of 10 on these newer trucks, hard starts are caused by low fuel pressure (even 1 psi low). If I recall, key on, engine off should be 65+ PSI, and engine running should be 55 psi. This pressure is checked with a guage on the Schrader valve on the fuel line. If your pressure is low, then it's usually either a clogged filter (which you have already replaced), a bad regulator, or a bad pump. In my experience, it's usually the pump. Many have told me it's usually the regulator, but on my fiancee`'s Jimmy, the regulator (original) is still good, but I've had to replace the pump twice due to hard/no start conditions.